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Italian Journal of Animal Science
ISSN: (Print) 1828-051X (Online) Journal homepage: http://www.tandfonline.com/loi/tjas20
Partial replacement of fish meal by T-Iso in
gilthead sea bream (Sparus aurata) juveniles diets
Giovanni Battista Palmegiano, Francesco Gai, Laura Gasco, Giuseppe Lembo,
Maria Teresa Spedicato, Pasquale Trotta & Ivo Zoccarato
To cite this article:
Giovanni Battista Palmegiano, Francesco Gai, Laura Gasco, Giuseppe Lembo,
Maria Teresa Spedicato, Pasquale Trotta & Ivo Zoccarato (2009) Partial replacement of fish meal
by T-Iso in gilthead sea bream (Sparus aurata) juveniles diets, Italian Journal of Animal Science,
8:sup2, 869-871
To link to this article: http://dx.doi.org/10.4081/ijas.2009.s2.869
Copyright 2009 Taylor & Francis Group LLC
Published online: 07 Mar 2016.
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869
Partial replacement of fish meal by T-Iso
in gilthead sea bream (Sparus aurata)
juveniles diets
Giovanni Battista Palmegiano
1, Francesco Gai
2, Laura Gasco
2,
Giuseppe Lembo
3, Maria Teresa Spedicato
3,
Pasquale Trotta
4, Ivo Zoccarato
21National Research Council - ISPA, Torino Division, Italy 2Dipartimento Scienze Zootecniche, Università di Torino, Italy
3COISPA, Italy
4National Research Council - ISMAR, Italy
Correspondig author: Laura Gasco. Dipartimento Scienze Zootecniche, Facoltà di Agraria, Università di
Torino. Via L. da Vinci 44, 10095 Grugliasco (TO), Italy - Tel. +39 011 6708574 - Fax: +39 011 6708563 - Email: laura.gasco@unito.it
AbstrAct - The aim of this study was the evaluation of microalga Isochrysis sp. T-Iso in partial
substitution of fish meal and the study of the effects on gilthead sea bream (Sparus aurata) perform-ances and chemical composition of fillets. The results show that the microalga T-Iso nutrients support growth better than control diets, and the chemical composition of sea bream fillets also meets the needs of consumers for healthy diets. T-Iso resulted highly digestible, and support the best perform-ances of fish fed on 70% alga diet probably due to its high protein efficiency in comparison to other diets. The presence of a high quantity of cyclic isoprenoid could explain this high efficiency of T-Iso. Gilthead sea bream fed on 70% T-Iso showed fillets with a low level of protein and a high level of fat; moreover, their somatic indexes were higher than those of fish fed other diets. Highest percentage T-Iso diet showed the highest amount of the sum of saturated fatty acids, mainly due to myristate and palmitate. On the contrary, the sum of polyunsaturated decreases, mainly because of the reduction of EPA and DHA amounts. If the mass production economical problems are solved, T-Iso will represent a good solution in partial substitution of fish meal.
Key words: T-Iso, Sparus aurata, Fatty acid, Fillet composition.
Introduction - The current trend in fish farming is towards increased use of plant protein in
com-mercial fish diets. In the last decade, much more attention has been paid to plant source of protein (Palmegiano et al., 2006). Microalgae are increasingly being used as feed in aquaculture for many marine organisms, because they constitute a source not only for energy, but also of many essential compounds such as the polyunsaturated fatty acids (Belay et al., 1996). The possible use of microalgae has been investigated as a nutrient for fish larvae as well as for juveniles and adults (Lu and Takeuchi 2004; Palmegiano et al., 2008). Among those algae, Isochrysis sp. showed to have high quality of nu-trients (CP: 43.0; EE: 18.7; Ash: 10.1; Crude fiber: 0.9; Total starch: 10.4 (99% gelatinized) and to be a good source of polyunsaturated fatty acids and in particular docosahaesenoic acid (DHA) (Trotta, 1998). The aim of this study was to evaluate a microalga (Isochrysis sp. T-Iso) as source of plant protein and ether extract in partial substitution of fish meal and fish oil, studing its effects on gilthead sea bream (Sparus aurata L.) performances and chemical composition of fillets.
Material and methods - Two hundreds and fourthy gilthead sea bream (22.3±0.3 g) were
ran-domly distributed in 12 tanks (100 l; water temperature constant at 18°C). Four diets were compared: Ital.J.anIm.ScI. vol. 8 (Suppl. 2), 869-871, 2009
870
proc. 18th nat. congr. aSpa, palermo, Italy
two experimental diets containing respectively 30% and 70% (on wet weight basis) of freeze-dried T-Iso and two control diets: the first as from a commercial diet for trout (closed formula) and the other one an extruded diet (closed formula). Diets were allocated to triplicate fish groups according to a com-pletely random experimental design. Fish were fed 1.2% of their body weight. Proximate analysis of algal masses and diets have been performed according to the AOAC methods (2000). Lipids, for the de-termination of fatty acid composition, were extracted according to Folch et al. (1957). Fatty acid methyl esters (FAME) were prepared by methylation procedure (AOAC 2000) and were separated and quanti-fied by gas chromatography (Perkin Elmer 8700). Fish were individually weighted at the beginning and at the end of the trial and in order to adjust the feeding quantities weighed in bulk every 15 days. The trial lasted 8 weeks and at the end performance indexes were calculated. Moreover, proximate fillet composition were determined following AOAC (2000) and viscera and hepatosomatic index were determined. Gross energy (GE) of diets and fillets samples was determined utilizing a calorimeter Ika C7000 (Heitersheim, Germany). Results were expressed as percentages and ratios were transformed in arcsin of roots; on transformed and normalized data variance analyses were performed by one way analysis of variance (A�OVA); significant differences were ranged (P≤0.05) by Duncan test.
results and conclusions - The chemical composition of the diets is reported in Table 1.
Fish readily accepted all experimental diets. Productive trait indexes (Table 2) showed a better in-dividual and biomass growth in sea bream fed on diet with higher microalga content. The T-Iso cellular wall is thin and make its nutrients more useful for sea bream to energy deposition. The relatively high gelatinised amount of carbohydrates well balances the protein energy ratio.
Growth perform-ances resulted in agree-ment with other stud-ies on the same specstud-ies (Lupatsch et al., 2001). The best performances of fish fed on 70% alga diet are probably due to its high protein ef-ficiency in comparison to other diets (2.0 vs 1.3-1.5), despite its lowest protein energy ratio. The little size (Ø≤70 µ) of the cells of T-Iso in comparison to the higher mesh of the other feedstuffs (Ø≈250 µ) could make easy the attack of the digestive juice, and consequently the absorption of the nutrients. VSI values are higher in extruded diet and in 70% alga diet than the values of the other two diets (4.9 and 5.0 vs 3.8 and 3.4
Table 1. Chemical composition of diets (mean ±sd).
Extruded diet Basal diet 30% T-Iso 70% T-Iso CP 49.5 ± 0.01 49.1 ± 0.4 43.9 ± 0.03 41.4 ± 0.1 EE 19.5 ± 1.4 6.1 ± 0.9 8.4 ± 0.3 11.8 ± 1.1 Ash 11.4 ± 0.03 11.8 ± 0.3 10.9 ± 0.01 9.6 ± 0.2 GE (Mj/kg) 21.6 ± 0.01 19.1 ± 0.03 19.2 ± 0.03 20.2 ± 0.01 DP/DE 2.9 ± 0.01 2.6 ± 0.02 2.3 ± 0.01 2.0 ± 0.01
Table 2. Productive traits during the experiment (8 weeks) (mean ±sd).
Extruded diet Basal diet 30% T-Iso 70% T-Iso Initial weight (g) 22.3 ± 0.2 22.9 ± 0.4 22.6 ± 0.1 22.5 ± 0.1 WG 6.9 ± 0.9b 7.1 ± 0.4b 7.3 ± 0.6b 9.1 ± 1.4a FCR 1.6 ± 0.1a 1.7 ± 0.2a 1.5 ± 0.1a 1.2 ± 0.1b SGR 0.9 ± 0.1b 0.9 ± 0.1b 0.9 ± 0.1ab 1.1 ± 0.2a PER 1.3 ± 0.1b 1.4 ± 0.1b 1.5 ± 0.1b 2.0 ± 0.2a HSI 1.1 ± 0.4 0.8 ± 0.6 1.0 ± 0.2 1.3 ± 0.3 VSI 4.9 ± 0.8a 3.8 ± 1.8b 3.4 ± 0.1b 5.0 ± 1.2a
a,b: P <0.05; WG=mean individual final weight–mean individual initial weight; FCR=total feed given (g of DM)/WG (g); SGR (% per day)=[(ln final weight-ln initial weight)x100/ t]; PER=WG (g)/amount of protein fed (g); HSI=(liver (g)/body in weight (g))x100; VSI=(viscera (g)/body in weight (g))x100.
Ital.J.anIm.ScI. vol. 8 (Suppl. 2), 869-871, 2009
871 proc. 18th nat. congr. aSpa, palermo, Italy
respectively). No statistically differences appeared for chemical composition of fillets (mean ± sd values: CP 49.6±1.7, EE 20.9±1.3, Ash 13.8±0.8, GE 22.4±0.7). As lipid composition of fillet are concerned (Table 3), differences in fatty acid profile were observed. In particular, the sum of saturated fatty acid in-creases in diets integrated with microalgae; this effect is mainly due to the high content in myristate (C14:0) and palmitate (C16:0). On the contrary, the sum of polyunsaturated decreases, mainly because of the reduction of Eicosapentaenoic acid (EPA - C20:5n-3) and Docosahaesenoic acid (DHA – C22:6n-3) amounts.
The decreasing of fillet linolenic acid (from 3.4% in 70% alga diet to 0.3% in fillet and from 1.6% in 30% alga diet to 0.3% in fillet) could mean that in fillets of gilthead sea bream fed T-Iso diets this fatty acid is elongated and desaturated, and transformed in EPA and in a lesser way in DHA.
The results of this study show that the microalga T-Iso nutrients support growth better than control diets, and the chemical composition of sea bream fillets also meets the needs of consumers for healthy diets. T-Iso resulted highly digestible, and support the best performances of fish fed on 70% alga diet are probably due to its high protein efficiency in comparison to other diets. Sea bream fed on 70% T-Iso showed a low level of protein and a high level of fat; moreo-ver, their somatic indexes were higher than those of fish fed other diets.
Highest percentage T-Iso diet showed the highest amount of the sum of saturated fatty acids, mainly due to myristate and palmitate. On the contrary, the sum of polyunsat-urated decreases, mainly because of the reduction of EPA and DHA amounts. If the mass production economical problems are solved, T-Iso will represent a good solution in partial substitution of fish meal.
references - AOAc, 2000. Official Methods of the Association of Official Chemists. 17th ed. Assoc. Official Methods of the Association of Official Chemists. 17th ed. Assoc. Off. Anal. Chem. Int., Arlington, VA. belay, A., Kato, T., Ota, Y., 1996. Spirulina (Arthrospira): potential ap-plication as an animal feed supplement. J. Appl. Phycol. 8:303-311. folch, J., Lees, M., Stanley, G.H.S., 1957. A simple methods for the isolation and purification of total lipids from animal tissue. J. Biol. Chem. 226: 497-509. Lu, J., Takeuchi, T., 2004. Spawning and egg quality of tilapia Oreochromis niloticus fed solely on raw Spirulina throughout three generation. Aquaculture 234:625-640. Lupatsch, I., Kissil, G.W.M., Sklan, D., Pfeffer E., 2001. Effects of varying dietary protein and energy supply on growth, body composition and protein utilization in gilthead seabream (Sparus aurata L.). Aquacult. �utr. 7:71-80. Palmegiano, G.B., Daprà, F., Forneris, G., Gasco, L., Gai, F., Guo, K., Peiretti, P.G, Sicuro, B., Zoccarato, I., 2006. Rice protein concentrate meal as potential ingredient in practical diets for rainbow trout (Oncorhynchus mykiss). Aqua-culture 258:357-367. Palmegiano, G.B., Gai, F., Daprà, F., Gasco, L., Pazzaglia, M., Peiretti, P.G., 2008. Ef-fects of Spirulina and plant oil on the growth and lipid traits of white sturgeon (Acipenser transmontanus) fingerlings Aquacult Res. 39:587-595. trotta, P., 1998. Componenti dietetiche, in biomasse di microalghe e filtratori zooplanctonti ottenute da catena trofica mirata, per la formulazione di diete di riferimento per pesci e crostacei di interesse per l'acquacoltura. Biol. Mar. Medit. 5(3): 1981-1996.
Table 3. Fatty acid profile of fillets (% of total fatty acids, mean ±sd).
Extruded diet Basal diet 30% T-Iso 70% T-Iso C14:0 8.1 ± 0.6 7.7 ± 0.3 9.0 ± 0.3 9.7 ± 0.2 C16:0 26.9 ± 0.6ab 26.2 ± 0.9b 27.5 ± 1.7ab 27.9 ± 1.5a C16:1 6.0 ± 0.3 6.1 ± 1.0 6.0 ± 0.4 5.8 ± 0.6 C18:0 5.1 ± 0.5 5.1 ± 0.5 5.2 ± 0.5 5.2 ± 0.7 C18:1 17.3 ± 1.0b 18.7 ± 0.6a 18.4 ± 0.0ab 17.6 ± 1.8ab C18:2n6 1.2 ± 0.1 1.5 ± 0.3 1.1 ± 0.1 1.1 ± 0.3 C18:3n6 0.3 ± 0.0 0.8 ± 0.1 0.3 ± 0.0 0.4 ± 0.0 C20:5n3 5.1 ± 0.3 5.1 ± 0.4 4.7 ± 0.2 4.5 ± 0.5 C22:6n3 6.3 ± 0.4 6.2 ± 0.2 5.2 ± 0.0 4.7 ± 0.4 SFA 44.7 ± 0.1 44.5 ± 1.7 46.4 ± 0.4 48.5 ± 2.3 MUFA 27.9 ± 0.3 29.8 ± 1.6 28.6 ± 0.7 27.6 ± 2.6 PUFA 19.1 ± 0.6a 18.7 ± 0.0ab 17.3 ± 0.0b 17.5 ± 0.3b DHA/EPA 1.2 ± 0.0a 1.2 ± 0.0a 1.1 ± 0.0ab 1.1 ± 0.0b a,b: P <0.05
Ital.J.anIm.ScI. vol. 8 (Suppl. 2), 869-871, 2009
